Let-off mechanism for looms



June 28, 1932. v. LINDSJO LET-OFF MECHANISM FOR LOOMS Filed Sept. 29. 1931 I N VEN TOR.

I/EENE L/NDSa/O.

W/T/VE 5 CLINTON S CoBU/ENQ A TTORNEY.

Patented June 28, 1932 UNITED STATES PATENT OFFICE VERNER LINDSJO, OF HOPEDALE, MASSACHUSETTS, ASSIGNOR TO DRAIER CORPORA- TION, OF HOPEDALE, MASSACI-IUS ETTS, A CORPORATION OF MAINE LET-OFF MECHANISM FOR LOOMS Application filed September 29, 1931. Serial No. 565,772.

This invention relates to looms, and more particularly to means forcontrolling the rate at whichthe warp sheet is let-ofi from the warp beam as the weaving progresses.

Let-off mechanism has heretofore been provided in which the rotation of the warp beam is controlled by means operating in timed relation to the other mechanism of the loom, and under control of various devices for governing the rate of rotation of the warp beam in accordance with the tension of the warp sheet. Such let-off mechanisms have usually been operated once during each complete reciprocation of the lay, that is, once for each pick.

I have found that the action of the take-up and of the shedding mechanism combine to produce such a tension on'the warp sheet as to render it desirable that the let-off should operate more frequently than once for each ick. p It is accordingly an object of my invention to provide a warp let-off mechanism with simple and efficient controlling devices for causing the letting-off operation to take place a plurality of times during each reciprocation of the lay.

Other objects of my invention willin part be hereinafter more specifically pointed out, and will in part become obvious as the description proceeds.

Referring more particularly to the drawing: 7 I

Fig. 1 is a view in elevation from the right hand side of a loom, and showing a let-off mechanism embodying my invention, and

Figs. 2 and 3 are detail views showing in full and dotted outline the various positions the parts of the let-ofl mechanism assume during their operation.

The various elements of the loom illustrated 3. The cloth as it is woven may be taken up by any'conventional form of mechanism now well known, and this take-up mechanism as well as the harness actuating mechanism are not illustrated or described, as they form no part of the present invention.

The warp beam is provided at one end with a head 10 having gear teeth out therein which cooperate with theteeth of a pinion 11. This pinion is fixed upon shaft 12 which is driven by internal gearing contained within a housing 13 and operated and controlled by a ratchet wheel 14. The foregoing parts .of the let-oil mechanism may conveniently be, and are illustrated as,'the same as those disclosed in Patent N 0. 647,815 granted April 17, 1900 to WV. F. Draper and O. F. Roper, or may be of any other suitable form.

The whip roll 8 is mounted in arms 15 on rock shaft 16 journalled in the loom frame.

arm 17 projecting from the rock shaft is pivoted at 23 to the bracket 20 on the loomside. The other arm 24 of the bell crank lever extends downwardly and is pivotally connected by a suitable stud (not shown) with the oscillating pawl carrier 25. The pawl carrier is herein shown as constituted by a lever fulcrumed intermediate its ends on shaft 12. The said pivotal connection may be positioned and controlled as in the above mentioned Draper et a1. patent. A spring 26 is connected at one end to the arm 24, and at the other end to an arm 27 fixed to the bracket 20.

It will thus be seen that the spring 26 serves to yieldingly urge the bell crank lever 22, 24 in a clockwise direction and thus to draw the pawl 28 over the teeth 29 of ratchet wheel 14 and position the pawl for an operating stroke. This retractile movement is limited in extent by the bent over end of the link 19, that is, the spring 26 will act upon the arm 24; and move it clockwise until the end of arm 22 contacts with the bent over end of the link 19 which position is controlled by the tension of the warp sheet.

I have provided devices operating in timed relation to the movements of the lay foriinparting to the pawl carrier two operating strokes during the interval required for the lay to make one complete reciprocation. Such devices may conveniently be constituted as follows:

A rod 30 is pivotally connected at one end, as at 31, to the upper arm of the pawl carrier 25. The lower end of this rod has an enlarged head portion 32 in which is formed a slot 33 positioned over pin 34. This pin 34 is carried by an operating member or arm 35 which is fixed to the rock shaft 36, and there- 'fore, reciprocates in unison with the lay. A rod 37 is pivotally connected at one end, as at 38, to the other arm 39 of the pawl carrier 25, this connection being on the opposite side ofthe fulcrum shaft 12 from the pivotal connection 31. The other end of rod 37 is provided with a head 40 having a slotted connection with pin 34:. The relative lengths of the rods 30 and 37, and the extent of the lost motion connections, are so proportioned as to cause each complete reciprocation of letoif operating member 35 to impart to pawl carrier25 two separate successive impulses in the same direction against the action of spring 26, the spring returning the pawl carposition after each impulse, Referring more particularly to Fig. 3 the parts are shown therein in full lines in the position they assume when the lay is in its extreme forward position. At this time the extreme outer end of the slot of the connection 40 is in contact with the pin 34, the slot 33 being long enough that the pin 34; does not contact the outer endthereof at this or any other time. The pawl carrier is advanced to the end of its operating stroke, and the spring 26 is stretched.

Movement of the lay from the full line position of Fig. 3 backwardly to its mid position results in movement of the operating member 35 to the dotted lineposition in Fig.

2. This movement causes pm 34to move to the right, and the action of spring 26 will keep the pin and the outer end of slotted connection .40 in contact until the pawl carrier has been fully withdrawn to its starting end position, that is, while the operating member 35 is moving in a clockwise direction from the full line position of Fig. 3 to the dotted line position of Fig. 2 the pawl carrier 25 will be moved. in a counter-clockwise direction by spring 26. Continued movement of the operating member in a clockwise direction,

while the lay moves from the said mid position to its extreme back position, results in pin 34; contacting the inner end of the slot 33 in connection 32 and thus moving the pawl carrier, through the rod 30 in a clockwise direction to eifect an operating stroke of the carrier.

\Vhen the lay has reached its extreme back position, the parts of the let-off mechanism will occupy the positions shown in full lines in Fig. 2. At this time the pawl carrier is advanced tothe end of its operating stroke and the pin 34 is in contact with the inner end of the slot 33 in connection 32. The slot in connection 40 is sufiiciently long that the pin does not contact the inner end thereof at any time. Movement of the lay from this back J'position forwardly to its mid position will result in the parts of the let-off mechanism moving from the full line position of Fig. 2 to the dotted line position of Fig. 3. In so moving the pin 34. tends to withdraw from contact with theinner end of the slot in connection 32 andallows spring 26 to again retract the pawl carrier to its starting end position. The final portion of the complete reciprocation of the lay is from its midjposition to its extreme forward position. While the lay is so moving the pin 3 T contacts with the outer end of the slot in connection40, thus rotating the pawl carrier 25-again ina clockwise direction. The parts are then again in the-position shown in full lines in Fig. 3. It will thus be seen that rod 3O acts through compression only, and rod 37 acts through tension only, to impart movement to the :pawl carrier.

' While -I have shown the rods 30 and 37 as slotted at their forward ends for cooper ation with a single pin on operating member 35, proper lost motion may be provided at the other ends of the rods, or in any other suitable manner, or other devices may be employed for operating the pawl carrier in the proper manner.

Considering the invention in its broader aspects, numerous other variations may be resorted to within the limits defined in the appended claims.

I claim:

1. In a loom, the combination of a recip rocating lay with a warp let-01f mechanism, said let-off mechanism including'gearing operated by'a single ratchet wheel for controlling the rate of advance of the warp sheet, an .oscillating .pawl carrier moving said ratchet wheel, an operating member recip- -rocating at the same rate asthe lay, and decontrolled by a single ratchet wheel, an osratchet wheel, a yielding cillating, pawl carrier causing movement of said ratchet wheel, an operating member reciprocating in unison with the lay, and devices connected to said operating member and operating in synchronism with the lay for imparting to said pawl carrier one complete oscillation during each half of each complete reciprocation of the lay.

3. In a loom, the combination of a reciprocating lay with a warp let-oil mechanism controlled by a ratchet wheel, an oscillating pawl carrier moving said ratchet wheel, an operating member reciprocating at the same rate as the lay, and devices including a pair of oppositely reciprocating rods connected to said operating member and operating in synchronism with the lay for imparting to said pawl carrier two complete oscillations during each complete reciprocation of the lay.

4. In a loom, the combination of a reciprocating lay with a warp let-off mechanism, said let-ofl' mechanism including gearing for governing the rate of advance of the warp sheet and a ratchet wheel operating said gearing, an oscillating pawl carrier moving said ratchet wheel, yielding means for moving the pawl carrier for one end of its stroke, an operating member reciprocating in unison with the lay, and devices connected to said operating member for moving said pawl carrier to the opposite end of its stroke twice during each complete reciprocation of the lay.

5. In a loom, the combination of a reciprocating lay with a warp let-ofi' mechanism, said let-ofi" mechanism including gearing con trolled by a single ratchet wheel for governing the rate of advance of the warp sheet, an oscillating pawl carrier for moving said whip roll having connections to a controller for varying one end position of the pawl carrier according to the tension on the warp sheet, yielding means urging the pawl carrier to the said end position, and devices including a pair of oppositely reciprocating rods operating in timed relation to the lay to positively move the pawl carrier to its other end position twice during each complete reciprocation of the lay. s

6. In a loom, the combination of a reciprocating lay with a warp let-0E mechanism, an operating member reciprocating in unison with the lay, an oscillatable let-oil operating lever fulcrumed intermediate its ends, yielding means for urging said lever in one direction, and devices extending from the arms. of the lever to the operating member and operable to impart to the lever at'least two successive movements at spaced intervals against the action of the said yielding means while the operating member is making one completereciprocation, whereby the let-ofl mechanism is operated at least twice during each complete reciprocation of the lay.

7. In a loom, the combination of a reciprocating lay with a warp let-ofl mechanism, an operating member reciprocating in unison with the lay, an oscillatable let-ofi' operating lever fulcrumed intermediate its ends, spring means for urging said lever in one direction, a rod extending between the lever at one side of its fulcrum and the operating member, and a second rod extending between the lever at the other side of its fulcrum and the said operating member,- with connections having lost motion of such relative location and extent as to cause the reciprocation of the said operating member in opposite directions to move the lever, through the rods, successively in the same direction against the action of the said spring, whereby the let-off mechanism is operated twice during each complete reciprocation of the lay.

8. In a loom, the combination of a reciprocating lay with a warp let-oil", an operating member reciprocating in unison with the lay, an oscillatable let-oif operating lever fulc-rumed intermediate its ends, spring means for urging said lever in one direction, a tension rod connecting one arm of the lever with the operating member and provided with a lost motion, and a compression rod connecting the other arm of the lever with the said operating member and also provided with a lost motion, said rods thereby imparting to the lever two successive movements against the action of the said spring while the operating member is making one complete reciprocation, whereby the let-oil is operated twice during each complete reciprocation of the lay.

VERNER LINDSJO.

the rods being provided 

